Fruit flies Drosophila melanogaster on old fruit. D. melanogaster is a small, common fly found near unripe and rotted fruit. It has been in use for over a century to study genetics. Nobel Laureate Thomas Hunt Morgan was the pre_eminent biologist studying Drosophila early in the 1900s. Morgan was the first to discover sex_linkage and genetic recombination, which placed the small fly in the forefront of genetic research. Due to its small size, ease of culture and short generation time, geneticists have been using Drosophila ever since. It is one of the few organisms whose entire genome is known, and many genes have been identified and numerous mutuations produced during the research.